Selected Hematology Abstracts From the 2016 ASCO Annual Meeting

Here are several abstracts selected from the proceedings of the 2016 ASCO Annual Meeting, focusing on clinical trials on therapeutics in different types of leukemia, multiple myeloma, follicular lymphoma, and central nervous system (CNS) lymphoma. For full details of these study abstracts, visit meetinglibrary.asco.org.

Question Asked: What is the treatment-free remission in specifically selected patients (n = 190) with CML in chronic phase following cessation of nilotinib (Tasigna)?

Abstract Conclusion: At week 48 of the treatment-free remission phase, 51.6% (95% confidence interval [CI]: 44.2%–58.9%) of the 190 patients were in major molecular response (see box) and had not reinitiated treatment. Of 86 patients who lost major molecular response and were restarted on nilotinib, 85 regained major molecular response (1 patient discontinued from the study [patient decision] without major molecular response 7.1 weeks after reinitiating nilotinib), and 76 regained molecular response 4.5.2 The median time to major molecular response and molecular response 4.5 among all patients who reinitiated nilotinib was 7.9 weeks and 13.1 weeks, respectively.2 No new safety signals were observed on treatment.

Abstract 7519: Venetoclax activity in chronic lymphocytic leukemia (CLL) patients who have relapsed after or are refractory to ibrutinib or idelalisib3

Abstract Conclusion: Yes. Fourteen of 22 ibrutinib-refractory patients and 3 of 5 idelalisib-refractory patients achieved response according to the International Workshop Group CLL criteria. Safety was consistent with prior reports with venetoclax. This is the first prospective study to demonstrate efficacy in this poor-prognosis population. Follow-up will assess the depth and duration of response in this ongoing study.

Question Asked: What are the safety and preliminary efficacy data of this entirely oral regimen in relapsed/refractory multiple myeloma?

Abstract Conclusion: Twenty patients were evaluable for toxicity. Full-dose ixazomib (Ninlaro) with standard-dose pomalidomide (Pomalyst) and dexamethasone was well tolerated. Preliminary response rates are promising, given that more than 50% of patients were dual-refractory and early into the course of treatment.

Abstract 7507: Effect of bortezomib on complete remission rate when added to bendamustine/rituximab in previously untreated high-risk follicular lymphoma: A randomized phase II trial of the ECOG-ACRIN Cancer Research Group (E2408)6

Question Asked: What is the added benefit of bortezomib on complete remission in combination with bendamustine/rituximab (Rituxan) in previously untreated high-risk follicular ­lymphoma?

Question Asked: Is the use of ibrutinib in heavily pretreated relapsed/refractory primary CNS lymphoma and secondary CNS lymphoma safe and tolerable?

Abstract Conclusion: A total of 10 patients were enrolled in the study, with 3 receiving 560 mg of ibrutinib and 7 receiving 840 mg of ibrutinib. Median age was 70 years (range, 21–80 years); 70% had primary CNS lymphoma and 30% had secondary CNS lymphoma. Six patients had parenchymal disease, three had isolated cerebrospinal fluid involvement, and one had both.

Treatment has been well tolerated, with two grade 4 toxicities (neutropenia and lymphopenia), which resolved after the drug was held. The most common toxicities observed were hyperglycemia, hypercholesterolemia, and thrombocytopenia.

After a median follow-up of 150 days, 9 patients were evaluated for response: 4 complete remissions (three in cerebrospinal fluid; one in the parenchyma), 3 partial remissions, and 2 progressive disease; the overall response rate was 78%. In a second treatment assessment, response has not been confirmed in two patients. Median time to first response was 28 days. Median progression-free survival was 6 months. Continued enrollment is ongoing, with a dose of 840 mg in an expansion cohort. ■